It has become more evident that long-term cigarette smoking (LTCS) has an important extrapulmonary toxicity. The aim of the study was to investigate the time-dependent effects of cigarette smoke ...exposure on exercise capacity, markers of systemic inflammation, and skeletal muscle structure. c57bl/6j-mice were either exposed to mainstream cigarette smoke for 6 h/day, 5 days/wk smoke-exposed (SE) group or assigned to the control, unexposed group (Con group). SE group mice were exposed for 8, 16, 24, and 32 wk to smoke and unexposed Con mice were used as age-matched controls. Exercise capacity was investigated by spiroergometry. Systemic inflammatory status was analyzed by flow cytometry and multiplexed fluorescent immunoassay. For analysis of muscle tissue, histological techniques and microarray analysis were used. Mice of the SE group exhibited a lower increase of body mass and a decrease of V̇o2 max (P < 0.05). An increase of lymphocyte CD62, ICAM, and VCAM expression was found in SE mice (P < 0.05). A biphasic trend of protein up- and downregulation was observed in markers of systemic inflammation, tissue deterioration, and allergic reactions such as C-reactive protein (CRP), eotaxin, haptoglobin, macrophage colony-stimulating factor-1 (M-CSF-1), and macrophage inflammatory protein-1γ (MIP-1γ). Thereby, the expression of several chemotactic proteins in plasma correlated with their expression in muscle. A time-dependent decrease of muscle mass, oxidative type-I fibers, and muscle cross-sectional area was found (P < 0.05). Microarray analysis revealed a SE-induced upregulation of several pathways of metabolic processes and tissue degradation. Taken together it was found that the loss of exercise capacity and systemic inflammation are early events of SE, which might induce muscular atrophy and loss of oxidative muscle capacity.
Purpose:
A breast dedicated positron emission tomography (PET) scanner has been developed based on monolithic LYSO crystals coupled to position sensitive photomultiplier tubes (PSPMTs). In this ...study, we describe the design of the PET system and report on its performance evaluation.
Methods:
MAMMI is a breast PET scanner based on monolithic LYSO crystals. It consists of 12 compact modules with a transaxial field of view (FOV) of 170 mm in diameter and 40 mm axial FOV that translates to cover up to 170 mm. The patient lies down in a prone position that facilitates maximum breast elongation. Quantitative performance analysis of the calculated method for the attenuation correction specifically developed for MAMMI, and based on PET image segmentation, has also been conducted in this evaluation. In order to fully determine the MAMMI prototype's performance, we have adapted the measurements suggested for National Electrical Manufacturers Association (NEMA) NU 2-2007 and NU 4-2008 protocol tests, as they are defined for whole-body and small animal PET scanners, respectively.
Results:
Spatial resolutions of 1.6, 1.8, and 1.9 mm were measured in the axial, radial, and tangential directions, respectively. A scatter fraction of 20.8% was obtained and the maximum NEC was determined to be 25 kcps at 44 MBq. The average sensitivity of the system was observed to be 1% for an energy window of (250 keV–750 keV) and a maximum absolute sensitivity of 1.8% was measured at the FOV center.
Conclusions:
The overall performance of the MAMMI reported on this evaluation quantifies its ability to produce high quality PET images. Spatial resolution values below 3 mm were measured in most of the FOV. Only the radial component of spatial resolution exceeds the 3 mm at radial positions larger than 60 mm. This study emphasizes the need for standardized testing methodologies for dedicated breast PET systems similar to NEMA standards for whole-body and small animal PET scanners.
A multi-shot target assembly and automatic alignment procedure for laser–plasma proton acceleration at high repetition rate are introduced. The assembly is based on a multi-target rotating wheel ...capable of hosting more than 5000 targets, mounted on a 3D motorized stage to allow rapid replenishment and alignment of the target material between laser irradiations. The automatic alignment procedure consists of a detailed mapping of the impact positions at the target surface prior to the irradiation that ensures stable operation of the target, which alongside the purpose-built design of the target wheel, enables operation at rates up to 10 Hz. Stable and continuous laser-driven proton acceleration at 10 Hz is demonstrated, with observed cut-off energy stability about 15%.
Increased interest in novel modulation formats for optical transmission has come up in recent years. Receivers with interferometric direct detection can be used to detect arbitrary modulation formats ...with differentially encoded phases as differential phase-shift keying (DPSK) and differentially phase-encoded star-shaped quadrature amplitude modulation (Star QAM). In this paper, two novel 16-ary modulation formats, which are the 16 DPSK and the Star 16 QAM (ASK-8 DPSK), are characterized for optical transmission for the first time. To be able to identify clear performance tendencies for high-order optical modulation, the novel formats are compared to a wide range of already investigated formats by conducting comprehensive calculations in a uniform simulation environment. The influence of different transmitter structures and decision schemes is considered, and all the systems are characterized with respect to the optical signal-to-noise ratio requirements, dispersion tolerance, and self-phase-modulation (SPM) performance for nonreturn-to-zero (NRZ) and RZ pulse shapes. Moreover, an inherent problem of Star QAM transmission concerning SPM is illustrated, and compensation techniques are examined. The results give a substantial insight into the properties of high-order optical modulation formats.
Laser Driven Plasma Accelerators (LDPA) can generate both characteristic and Bremsstrahlung x-rays in ultrashort bunches. Because of the high intensity of the laser pulses, these laser-induced x-ray ...sources can achieve peak dose rates compatible with the FLASH regime. At the Laser Laboratory for Acceleration and Applications (L2A2/USC), a setup for the irradiation of
in vitro
cell cultures with a laser-driven x-ray source has been developed. The suitability of this source for studying the influence of Ultra High Dose Rates (UHDR) on DNA damage has been proven through the irradiation of
in vitro
cell cultures.
In Positron Emission Tomography (PET) detectors based on monolithic scintillators, the photon interaction position needs to be estimated from the light distribution (LD) on the photodetector pixels. ...Due to the finite size of the scintillator volume, the symmetry of the LD is truncated everywhere except for the crystal center. This effect produces a poor estimation of the interaction positions towards the edges, an especially critical situation when linear algorithms, such as Center of Gravity (CoG), are used. When all the crystal faces are painted black, except the one in contact with the photodetector, the LD can be assumed to behave as the inverse square law, providing a simple theoretical model. Using this LD model, the interaction coordinates can be determined by means of fitting each event to a theoretical distribution. In that sense, the use of neural networks (NNs) has been shown to be an effective alternative to more traditional fitting techniques as nonlinear least squares (LS). The multilayer perceptron is one type of NN which can model non-linear functions well and can be trained to accurately generalize when presented with new data. In this work we have shown the capability of NNs to approximate the LD and provide the interaction coordinates of γ-photons with two different photodetector setups. One experimental setup was based on analog Silicon Photomultipliers (SiPMs) and a charge division diode network, whereas the second setup was based on digital SiPMs (dSiPMs). In both experiments NNs minimized border effects. Average spatial resolutions of 1.9 ±0.2 mm and 1.7 ±0.2 mm for the entire crystal surface were obtained for the analog and dSiPMs approaches, respectively.
Phase diversity (PD) receivers are an elegant option to handle the phase noise at homodyne detection and are especially interesting when used as wideband tunable wavelength-division multiplexing ...receivers. In the late 1980s and early 1990s, they were proposed and investigated for binary modulation formats (amplitude-shift keying, differential phase-shift keying, and frequency-shift keying). In this paper, a homodyne PD receiver for differential quadrature phase shift keying (DQPSK) modulation is analyzed, which provides a promising alternative to presently investigated DQPSK-direct-detection receivers and homodyne receivers with digital phase estimation
At the Mainz Microtron the electric form factor of the neutron,
G
E,
n
, has been measured in two kinds of double polarisation experiments. The most recent results have been obtained by recoil ...polarimetry from the quasi-elastic
D
(
e
→
,
e
′
n
→
)
p
reaction at squared four-momentum transfers
Q
2
=
0.3
,
0.6
,
and
0.8
(
GeV
/
c
)
2
. A further data point at
0.67
(
GeV
/
c
)
2
has been extracted from quasi-elastic scattering of polarised electrons on
H
→
e
3
. We present the methods and results of our experiments as well as an overview on the precise
G
E,
n
data available at present.
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